The present invention relates generally to detectable security markings. More specifically, the present invention relates to optically encoded phosphorescent and fluorescent security markings that range in wavelength from the ultraviolet to the far infrared spectral regions.
Counterfeiting and forgery have become significant concerns in the modern economy and marketplace. While fraudulent activities such as counterfeiting currency and forging signatures or handwriting are common, methods of creating and perfecting forgeries and counterfeit documents have become easier and more available with the advent of highly skilled computer printing and processing. Given the advances and reduction in cost of computing technology and printing techniques, the incidence of forgeries, counterfeited documents, and other fraudulent activities have increased. This is problematic in that countless areas of today's high-technology society require and rely upon certification, authentication and protection of highly valuable documents, papers, currency or other materials in order to prevent fraud and counterfeiting. In an attempt to combat the use of counterfeit money, for example, the United States Treasury, as far back as 1991, has continually added security safeguard features to the various denominations of currency. These safeguards have included watermarks, security threads embedding in the paper, microprinting, color-shifting ink, and the use of multi-colored bills.
Generally, current methods of authentication of currency involve visual observation scanning under ultraviolet lamps notes containing security threads and emissive materials such as inks and planchettes. Such security threads emit a distinct marking, color or code in response to exposure to the ultraviolet light. In some circumstances, the emissive features of different denominations of notes can emit different colors. In addition to the colors of the emission, a code number or other unique identifier can be detected by the naked eye when the note is exposed to ultraviolet light or excitation of some form.
In addition to protecting against counterfeit currency, authentication of valuable documents or materials also affects many facets of the economy. For example, notaries public use a raised stamp to authenticate notarized documents; drivers' licenses, passports and other photographic identification contain holograms and microprinting; sporting memorabilia and retail clothiers use holographic tags and stamps to prove authenticity. Even fashion designers are now including authentication devices in their clothing to prevent passing off of knock-offs as designer products.
A disadvantage to these traditional security features is that they are visible and known to the world. If a counterfeiter is aware there is a security thread in a bill or a watermark in a document, replication of the security feature is easier. Once a feature is made known to the public, a counterfeiter may begin to develop specific strategies and solutions to overcome the security protections provided by the specific feature.
Accordingly there is a need for a covert security marking to be incorporated into currency, important and valuable documents, packaging, and other authentic materials to prevent unauthorized copying, forging, counterfeiting and other fraudulent use.